This application claims the priority of Japanese Patent Application No. 10-338901 filed on Nov. 30, 1998, which is incorporated therein by reference.
1. Field of the Invention
The present invention relates to an endoscope insertion guide tube, and more specifically a configuration of a leading end of a guide tube which is used to insert a scope for digestive organs into a body to be observed.
2. Description of the Prior Art
For insertion of an endoscope (scope) for digestive organs into a body to be observed (for example a scope for small intestine), it is conventional to use a guide tube to aid insertion by maintaining straight an otherwise meandering insertion path of the digestive organs.
A condition of a guide tube which is in a condition disposed in digestive organs is shown in FIGS. 4(A) and 4(B), wherein a guide tube 1 is passed from a stomach 2 to a duodenum 3 and a scope 4 is led to the duodenum 3 or a small intestine under the duodenum while being guided by the guide tube 1, for example, as shown in FIG. 4(A). The guide tube 1 facilitates insertion of the scope 4.
However, the conventional guide pipe 1 allows a gap S to remain between the guide tube 1 and the scope 4 as shown in FIG. 4(B), thereby posing a problem that the scope 4 slightly moves (rattles) in the guide pipe 1 in a diametrical direction and is not stable in its position. Furthermore, a leading end port of the guide tube 1 may be slightly opened by a bending or the like of the scope 4, whereby a surface wall portion 5 of a body to be observed may be pinched in the gap S when the scope 4 is inserted or withdrawn. The gap S of a certain degree is necessary to smooth insertion of the scope 4 and cannot be eliminated completely.
Furthermore, there is available a conventional guide tube such as one disclosed by Japanese Patent Laid-Open No. 10-248799 using an auxiliary tube which is made of a flexible material and has a bulb portion having a circular sectional shape at a leading end so that the spherical portion is brought into close contact with an outer circumference of a scope. However, such an auxiliary tube which has flexibility allows the leading end to be deformed, thereby making it difficult to insert the scope or the auxiliary tube into a digestive organ.
FIGS. 5(A) and 5(B) show a condition of a guide tube which is deformed as described above, wherein a leading end of the guide tube 1 is inserted into a body and deformed into an elliptic shape as shown in FIG. 5(A) under an internal pressure, thereby making it hard to pass the scope 4 through a bulb portion 6 of the leading end. Furthermore, the guide tube 1 cannot hardly be moved for insertion of withdrawal along the scope 4 which as been inserted.